public class Example4_20 {
    public static void main (String args[]) {
        char a[]={'a','b','c','D','E','F'};
        for (int i=0;i<a.length;i++){
            if (Character.isLowerCase(a[i]))
                a[i]=Character.toUpperCase(a[i]);
            else if (Character.isUpperCase(a[i]))
                a[i]=Character.toLowerCase(a[i]);
        }
        for (int i =0;i<a.length;i++)
            System.out.println(" "+a[i]);
    }
}
